Thermoplastic olefins (TPO's), which typically comprise polypropylene and an elastomer, have many desirable properties, e.g., lightweight, durability, low cost, etc., that make them an attractive material of construction for many interior and exterior automotive parts.
Many of the automotive parts manufactured from TPO's are painted to improve the aesthetic quality of the automotive part. For instance, automobile bumpers formed from TPO's are often painted to match the color of the rest of the automobile's exterior paint. Accordingly, it is an object of the present invention to provide TPO's having acceptable paint adhesion.
As the use of painted TPO automotive parts has become more prevalent, it has been observed that painted TPO automotive parts are relatively susceptible to damage known as compressive-shear induced delamination (i.e., gouging) as a result of compressive shear loads acting on the part. An example of such a compressive shear load is a shopping cart impacting an automobile bumper. Accordingly, it is a further object of the present invention to provide TPO's having acceptable paint adhesion and gouge resistance for use in the manufacture of automotive parts.